Blackboard



(No Model.)

G. J. SCHNEIDER & K. F. G. BRENNER. BLAGKBOARD.

No. 604,422. PatentediMay 24, 1898. 3,;0

UNITED STATES PATENT @rrron.

GUSTAV J. SCHNEIDER, OF SHEBOYGAN, AND KARL F, G. BRENNER, OF

KAUKAUNA, WISCONSIN.

BLACKBOARD.

SPECIFICATION forming part of Letters Patent No. 604,422, dated May 24,1898. Application filed March 20,1897. semi ne'azasse. (No model.)

To all whom it may concern.-

Be it known that we, GUSTAV J. SCHNEIDER, of Sheboygan, in the countyofSheboygan,

and KARL F. G. BRENNER, of Kaukauna, in

the county of Outagamie, State of Wisconsin, have invented a new anduseful Improvement in Adjustable Blackboards, of which the following isa description, reference being had to the accompanying drawings, whichare a part of this specification.

Our invention relates to improvements in adjustable blackboards.

It is the object of our invention to provide an adjustableblackboardwhich is easy of manipulation, simple in construction, inexpensive ofproduction, and can by improved means be readily raised or lowered tosuit the convenience of the user.

Having the above object in view, the invention consists of the devices,and parts or their equivalents, as hereinafter more full pointed out,

In the accompanying drawings, Figure 1 is a front elevation of ourimprovements, a part being broken away. Fig. 2 is a vertical transversesection on the line 2 2 of Fig. 1. Fig. 3 is a horizontal section on theline 3 3 of Fig. 1, and Fig. 4 is a detail.

Referring to the drawings, the numerals 5 5 indicate two side boxeswhich extend from the floor or support 6 upwardly for a desireddistance. These side boxes are united at their upper ends by aconnecting-piece 7, which may also be in the form of a box, as clearlyshown in Fig. 2. Mounted in the opposite ends of this connecting-box 7are pulleys 8 8. Over these pulleys pass cords or equivalents 9 9. Thesecords extend down into the vertical boxes 5 and are connected to theupper ends of coiled springs 10 10, arranged within said boxes, thelower ends of said springs being connected to screw-eyes 11 ll.

The numeral 12 indicates the blackboard, which is advisably surroundedby an ordinary form of frame 13, the lower strip of said frame beingprovided with an outWardly-pro jecting ledge 14, which is adapted tosupport chalk and may also be advantageously used as a hand-grasp. Theside pieces of the frame are provided with projecting tongues 15 15,

which are adapted to fit and slide in vertical grooves 16 16, formed inthe inner sides of the boxes 5. The upper strip of the frame has screwedtherein at opposite ends the eyes 17 17, and to these eyes the ends ofthe portions of the cords 9, whichare outside of the boxes 5, connect.

While we prefer to surround the blackboard with a frame similar to 13,yet it will be understood that, if preferred, this frame may be entirelyomitted and the ends of the blackboard proper be extended into thevertical grooves 16 and the cords 9 connected directly to the upper edgeof said board.

On the back of the board and intersecting the same medially are seriesof teeth 18, arranged in a Vertical line and forming a rackbar. Back ofthe board is also disposed a vertical boxing or casing 19. In thiscasing is pivoted medially upon a pin 20 a lever 21. The upper end ofthis lever is provided with a hook, which is adapted to extend throughan opening 22 in the front of the boxing 19 to engage any of the seriesof teeth of the rack-bar 18. The lower end of this lever is providedwith a recess 23, into which is adapted to fit the upper roundedextremity of the vertical member of a bell-crank lever 24, which ispivoted within the boxing on a pivotpin 25. The horizontal member ofthis bellcrank lever extends through an opening 26 and is in the form ofa treadle in convenient position to be operated by the foot. Secured tothe bottom of the boxing or casing 19 is a flat spring 27. This springextends through the opening 26, and its free end is adapted to bearagainst the under side of the horizontal member of the bell-crank lever.

It will be understood that the coiled springs 10 normally hold theblackboard at the upper end of the framework formed by the side and topboxes or casings. If now it is desired to Write on the board and tobegin the writing at the upper portion of said board, pressure isexerted upon the foot-treadle, and this will have the effect of turningthe lever 21 on its pivot, so as to release its hooked end fromengagement with one of the teeth of the rackbar. The projecting ledge 14is then grasped by the hand and the board pulled down to the properposition-as, for instance, to the position shown in Fig. 1. Pressure onthe foottreadle is then removed, and the flat spring 27 will have theefiect of automatically turning the lever 21 on its pivot, so as tobring the upper hooked end of said lever again in engagement with one ofthe teeth of the rackbar, whereby the board is held to adjustedposition. It is obvious from this description that the board can be mostquickly and conveniently adjusted to any desired position in the spacebetween the top connecting-piece and the floor.

In order to render the movements of the blackboard as far as possiblenoiseless, we secure in the grooves in the side boxes 5 felt linings 28,against which the tongues 15 bear.

What we claim as our invention is-- In an adjustable blackboard, thecombination, of a frame, the side pieces thereof be ing in the form ofboxes or casings, a blackboard slidable between the side boxes andhaving a rack-bar formed thereon, coiled cured to the blackboard andtheir opposite ends secured to the coiled springs, a vertical boxing orcasing, a lever pivoted therein, and having one end passing through anopening in its boxing in order to engage the rack-bar, a spring adaptedto normally hold the lever in engagement with the rack-bar, and abellcrank lever pivoted within the vertical box or casing, and havingone end engaging the other lever, and its opposite end passing throughan opening in the boxing or casing in position to be operated.

In testimony whereof we affix our signatures in presence of twowitnesses.

GUSTAV J. SCHNEIDER. KARL F. G. BRENNER.

Witnesses as to Schneiders signature:

JOHN SCHOEMER, MARTIN JURIcK. Witnesses as to Karl F. G. Brennerssignature:

F. A. TowsLEY, E. M. TowsLEY.

